Process for preparation of amphoteric polyurethane emulsions

ABSTRACT

A process for the preparation of amphoteric polyurethane emulsions comprising chain-extending a urethane prepolymer having isocyanate groups at the ends of the molecule by reacting it with a polyalkylene polyamine having at least two primary or secondary amino groups and also having a functional group of the formula:

United States Patent 11 1 Matsuda et al.

[4 1 Sept. 2, 1975 1 PROCESS FOR PREPARATION OF AMPHOTERIC POLYURETHANE EMULSIONS [75] Inventors: Kazuo Matsuda; Hidemasa ()hmura:

Hirakazu Aritaki, all of Wakayama. Japan [73] Assignee: Kao Soap Co.. Ltd., Tokyo Japan [22] Filed: Sept. 13, 1974 [21] Appl. No.: 505,679

[30] Foreign Application Priority Data Sept. 18. 1973 Japan 48-105301 [52] US. Cl. 260/29.2 TN; 260/75 N;

260/77.5 AM; 260/584 R [51] Int. Cl.'- C08G 18/32; C08] 3/06 [58] Field of Search 260/584 R 77.5 AM.

[56] References Cited UNITED STATES PATENTS 3,278.560 10/1966 Gacrtner 260/584 R 3.419.533 12/1968 Dieterich 260/292 TN 3,479,310 11/1969 Dieterich et al... 260/292 TN 3,491,050 1/1970 Keberlc et al. 260/292 TN 3.836 493 9/1974 Matsuda ct a1 260/292 TN Primary E.\'wniner.lohn C. Bleutge Assistant E.\'aminerArthur H. Koeckert Attorney, Agent, or FirmWoodhams, Blanchard and Flynn [57] ABSTRACT A process for the preparation of amphoteric polyurethanc emulsions comprising chain-extending a urethane prepolymer having isocyanate groups at the ends of the molecule by reacting it with a polyalkylene polyamine having at least two primary or secondary amino groups and also having a functional group of the formula:

CH CH(OH)CH X wherein X is C1 or Br. to form a polyurethane-ureapolyamine. rendering the amino groups of the resulting product amphoteric by reacting the resulting product with an amphoteric compound in an amount sufficient to emulsify the final polymer, said amphoteric compound being selected from the group consisting of 1,3-propanesultone, 1,4-butancsu1tone B-propiolactone. y-butyrolactone. e-caprolactone. fi-valerolactone and sodium monohalogenated carboxylates having the formula X(CH COONa in which X is halogen and n is an integer of l or 2 or by reacting the resulting product with a compound selected from the group consisting of methyl acrylate, ethyl acrylate, methyl methacrylate. ethyl methacrylate and acrylonitrile and hydrolyzing the resulting reaction product. and then mixing the resulting amphoteric polymer with water.

9 Claims, N0 Drawings PROCESS FOR PREPARATION OF AMPHOTERIC POLYURETHANE EMULSIONS BACKGROUND OF 'l'Hl-I INYEN'HON l. Field of the Invention v y This invention relates to a process for preparing polyurethane emulsions. More particularly. this invention relates to a process for preparing homogeneous stable amphoteric selfemulsifiahle polyurethane emulsions.

2. Description of the Prior Art Various processes for the preparation of polyurethane emulsions have been known in the art. For example. an emulsifier-free polyurethane emulsion. namely. a so-called self-emulsifiable polyurethane emulsion. can be prepared by a process comprising reacting a polyhydroxyl compound with an excess of an organic polyisocyanate to form a urethane prepolymer having terminal isocyanate groups. chain-extending the urethane prepolymer with an active hydrogen atomcontaining chain extender to form a polyurethane having primary or secondary amino or hydroxyl groups. reacting the resulting product with a sultone. a lactone or the like anti mixing the reaction product with water.

According to another known process. a polyurethane composition can be dispersed in water in the presence of an emulsifier.

In general. polyurethane resins have excellent physical and chemical properties. In practical use of polyurethane emulsions. however. there is a serious problem. More specifically. the physical and chemical properties of polyurethane resin films obtained from polyurethane cniulsions prepared according to conventional processes. such as those mentioned above. are greatly inferior to the physical and chemical properties of films made of cross-linked type polyurethane resins. because it is difficult to introduce the cross-linkages in the polyurethane by chemical means or because of the presence of residual emulsifier in the polyurethane resin.

in general. when a polyurethane-containing polymer having tight cross-linkages is used. handling of the poly mcr during the preparation steps is very difficult .because the polymer is infusible and insoluble. Accordingly. it is substantially impossible to obtain an emulsion by dispersing such a polymer into water. and even if such polyurethane polymer can be dispersed in water. in many cases the resulting emulsion is very unstable.

As an effective measure for overcoming this problem. there can be mentioned a process comprising reacting a urethane prepolymer with an excess of a polyalkylene poly-amine. reacting the resulting polyurethane-urea-polyamine with an epihalohydrin. reacting the resulting product with the sultone. lacto'ne or sodium monohalogenated carboxylatc in an amount sufficient to emulsify the final polymer. and mixing the resulting reaction'product with water to form a polyurethane emulsion. However. in this process. because the reaction between the polyurethane-urea-polyamine and cpihalohydrin is conducted in a polymeric system. the reactivity of thepolyurethane-urca-polyamine is low and hence. in many cases cross-linl ages are not formed at a sufficient density in the heat-treated films prepared from the emulsions prepared according to this process.

it- -\.T SUMMARY OF THE lNVEN'l'lON We have discovered amphotcric self-emulsifiahle polyurethane.emulsions containing a functional group having a eross-linsage-forming property.

More specifically. we have discovered that the halohydrin structure is very effective as a reactive functional group for forming cross-linkages during the heat treatment of a polyurethane resin. and that a polyalkylene polyamine having a functional group of the formula -(H- --CH(OH)--CH- X. in which X is Cl or Br. is very effective as a compound for both chain-extending a urethane prepolymer and introducing a selected amount of a halohydrin group into the resulting polymer.

In accordance with this invention. there is provided a process for preparing amphoteric polyurethane emulsions which comprises chain-extending a urethane prepolymer having terminal isocyanate groups. which is prepared from a polyhydroxyl compound and an excess of a polyisocyanate. with a polyalkylene polyamine having a functional group represented by the formula CH- CH(OH CH- ,X. in which X is C1 or Br. thereby to form a polyurethane-urea-polyamine reacting the thus-formed product amphoteric with a sultone. lactone or sodium monohalogenated carboxylate. or with an acrylate or acrylonitrile followed by hydrolysis. and mixing the resulting reaction product with water thereby to form an amphoteric self-emulsifiable polyurethane emulsion. ,The resin component in the thusformed polyurethane emulsion either has no crosslinkages or it has only a very small number of crosslinkages. When a polyurethane resin film obtained by drying this polyurethane emulsion is heat-treated. tough cross linkages are formed and the physical and chemical properties of the polyurethane resin are highly improved. This specific property of the polyurethane emulsion. according to this invention. is one of the prominent advantages of this invention.

The polyalkylene polyamine having a functional group of the formula CH CH(OH)CH- ,X. in which X is Cl or Br. which is used in this invention as a chain extender fora urethane prepolymer. is a reaction product obtained by reacting a polyalkylene polyaminc with an epihalohydrin such as epichlorohydrin and epibrornohydrin. ,It has the following formula l wherein X is Cl or Br. A is a secondary or tertiary amino group and R is an alkylene group having at least one primary or secondary amino group. with the pro viso that the compound represented by the general formula includes at least two primary or secondary amino groups.

Accordingly. a polyurethane-urea-polyamine obtained by chain cxtending a urethane prepolymer with a chain extender having the formula l contains a halohydrin structure in the molecule. Because of the presence of this halohydrin structure. tough cross-linkages are formed when a film. of the resulting emulsion is heated.

The polyurethaneurea-polyaminc used in this invention isobtained byrcacting a urethane prepolymer hav- 3 ing terminal isocyanate groups. whith is derived from a polyhydroxyl compound and an excess of a polyfunctional isocyanate. with a chain extender of the formula l preferably in ketone type solvent. such as acetone or methyl ethyl ketone.

As the polyfunctional isoeyanate. there can be employed. for example. aromatic. aliphatic and alicyclic diisocyanates such as 1.5-naphthylene diisocyanate. 4.4'-diphenylmethane diisocyanate. 4.4- diphenyldimethylmethane diisocyanate. di-and tetraalkyldiphenylmethane diisocyanates. 4.4'-diben7.yl diisocyanate. l.3-phenylene diisocyanate. l.4-phenylene diisocyanate and tolylene diisocyanates. chlorinated isoeyanates. brominated isocyanates. phosphoruscontaining isocyanates. l.4-butylene diisocyanate, 1.6- hexamethylene diisocyanate. lysine diisocyanate. dicyclohexylmethane diisocyanate. cyclohexanel .4- diisocyanate. Xylene diisocyanate. and the like. Further. it is possible to employ triisocyanates such as lmethylbenzol-2.4.o-triisoeyanate. biphenyl-2.4 4'- triisocyanate and triphenylmethane triisocyanate in combination with the above-mentioned diisocyanates.

The polyhydroxyl compounds used in the preparation of a urethane prepolymer to be used in the process of this invention are those having a molecular weight of 200 to 10.000. Any of the known polyhydroxyl compounds customarily used for the preparation of poly urethanes. such as polyethers. polyesters. polyester am ides. polyacetals. polythioethers. polybutadieneglycols and the like can be used in this invention.

As the polyether. there can be mentioned. for example. cyclic others such as those obtained by the ringopening polymerization or copolymerization of ethyl ene oxide. propylene oxide. butylene oxide. tetrahydrofuran and the like. and graft copolymers thereof.

Further. homogeneous polyethers or mixed polyethers formed by condensation of. for example. hexanediol. methylhexanediol. heptancdiol and octanediol can be employed. It is also possible to use propoxylated and ethoxylatcd glycols.

As typical examples of the polyester. there can be mentioned polyester glycols obtained by dehydrogenating condensation of dibasic acids and saturated or unsaturated low-molecular-weight glycols such as ethyleneglycol. propylcneglycol. 1.3-butanediol. 1.4- butanediol. neopentylglycol. pentanediol. hexanediol. octanediol. Z-ethyl-l.3-hexanediol. l.4-butynediol. bisphenol A. diethyleneglycol. dipropylencglycol and the;

like. and polyester glycols obtained by ring-opening polymerization of cyclic ester compounds.

As the polythiocther. there are preferably employed homopolycondensation products of thioglycols and copolycondensation products of thioglycols with other glycols.

As the polyacetal. there can be mentioned. for example. water-insoluble polyacetals derived from hexanediol or 4.4-dioxyethoxydiphenylmethane and formaldehyde.

Glycols customarily used together with the above polyhydroxyl compounds. such as ethyleneglycol, diethyleneglycol. triethyleneglycol. butanediol. propanediol. 1.6-hexanediol. neopentylglycol and N- alkyldiethanol amines having an alkyl group of one to 22 carbon atoms can be used in combination with the polyols. if necessary.

As the polyalkylene polyamine used in the process of this invention. there can be used various polyalkylene polyamines such as polyethylene polyamine. polypropylene polyamine. polybutylene polyamine and the like in this invention.

More particularly. the polyalkylene polyamine used in this invention are polyamines containing in the molecule from two to about four connecting units having the formula -C,,H wherein n is an integer larger than one. usually from 2 to 6. The connecting units connect together the nitrogen atoms. The nitrogen atoms may be bound to adjacent carbon atoms in the C,,H unit but they may not be bound to the same carbon atom.

The polyamines have the formula wherein n is as defined above. is an integer from 2 to 4. and R. which can be the same or different. are hydrogen. alkyl having one to four carbon atoms or bydroxyalkyl having one to four carbon atoms.

More specifically. there can be used not only such polyamines as diethylene triamine. triet'hylene tetraminc. tctraethylcne pcntamine and dipropylene triamine but also mixtures and various crude products containing these polyamines.

It is also possible to use hydroxyalkyl-substituted polyamines in combination with the foregoing polyamines.

In some cases. in order to change the density of hydrophilic groups in the polyurethane emulsion obtained according to this invention or to improve the properties of the films made from the emulsion. it is preferred to change or increase the distance between the active hydrogen-containing amino groups in the polyurethane-urea-polyaminc molecule. This can be accomplished by substituting a part of the polyalkylene polyamine. with ethylene diamine. propylene diamine. hexamethylene diamine. piperazine, phenylene diamine. a substitution product of such diamine with a saturated alkyl group of one to 22 carbon atoms. or an alkyleneoxide adduet. acrylonitrile adduet or acrylate adduet of such diamine. In general. the foregoing object can be achieved by replacing up to about 50 molar percent of the polyalkylene polyamine by the diamine.

As the epihalohydrin to be used for preparing the chain extender of the formula l by reaction with the above polyalkylene polyamine. epichlorohydrin and epibromohydrin are effectively used. but epiehlorohydrin is preferred. The polyalkylene polyamine used is selected so that the chain extender of the formula l contains at least two amino groups and at least two of the amino groups contained are primary or secondary amino groups. When the polyalkylene polyamine is re acted with the epihalohydrin to form a chain extender of the formula l it is preferred that both are reacted in the presence of an inert organic solvent. such as benzene.

In the reaction between the polyalkylene polyamine and epihalohydrin. the ratio of the two reactants differs depending on the number of amino groups contained in one molecule of the polyalkylene polyamine. but this ratio should be selected so that at least two primary or secondary amino groups are contained in one molecule of the product of the formula l This reaction is generally conducted at a temperature of to 80C. When the reaction is carried out at too high a temperature. the product becomes resinous.

The reaction time varies depending on the reaction temperature and the kind of polyalkylene polyamine used. but it is generally preferred that the reaction is conducted for 0.5 to 5 hours. I v

Preparation of the isocyanate-terminated urethane prepolymcr used in this invention is carried out in the presence of an inert solvent. such as benzene. or without a solvent.

When an aromatic polyisocyanate is used with the polyhydroxyl compound, a reaction temperature of 50 to 100C is used. and when an aliphatic or alicyclic polyisocyanate is employed. a reaction temperature of 70 to 130C is adopted. I

In the preparation of the urethane prepolymcr. it is preferred that the amount of the polyisocyanate is sc lcctcd so that all of the hydroxyl groups are reacted with the isocyanate groups of the polyisocyanate.

More specifically. it is preferred that the ratio of the total mole number of the NCO groups to the total mole number of the reactive hydrogen atoms OH groups) is within the range of from 1.] 1.0 to 5.0 L0.

The reaction between the isocyanateterminatcd urethane prepolymer and the chain extender of theformula (l) is preferably conducted under atmospheric pressure at a temperature ranging from to +70C in a kctone'type solvent.

As the ketone type solvent. there can be employed. for example. acetone, methylcthylketonc. diethylketone. dipropylketone. methylisobutylkctone and methylisopropylketone. Use of acetone and mcthylethylketone is especially preferred.

It is possible to employ a mixed solvent of a kctonc type solvent with benzene. tetrahydrofuran. dioxane. an acetic acid ester. dimcthylformamide or a chlorinated solvent.

The reaction time varies depending o the reaction temperature and the reactivity of the polyisocyanate compound used. A shorter or longer reaction time is adopted depending on the reaction conditions. The reaction is continued until the absorption at 2.250 cm" owing to the NCO group disappears in the infrared absorption spectrum measured on samples of the reaction mixture taken during the reaction. In general. the reaction is carried out for 0.5 to 2 hours.

In the reaction of the isocyanate groups at both ends of the urethane prepolymcr molecule with the chain extender of the formula (I it is critical that the total mole number of the primary and secondary amino groups is greater than the total mole number of the isocyanate groups. As the total mole number of the amino groups becomes close to the total mole number of the isocyanate groups. the molecular weight of the result ing polyurethane-urea-polyamine becomes great. and a gelled product or a product having a great tendency to become gclatcd is formed. If the mole number ratio of the amino groups to the isocyanate groups is too high. the molecular weight of the resulting polyurethaneurca-polyamine becomes small. and if such a lowmolecular-weight polyurethane-urea-polyamine is used as an intermediate for preparing the polyurethane emulsion. it is impossible to obtain a resinous product of excellent physical properties from such an emulsion. It is preferred that the ratio of the number (B) of moles of active hydrogen-containing amino groups in the chain extender of the formula l to the number (A) of moles of isocyanate groups in the isocyanateterminated urethane prepolymcr is within the range of l B/A 5. especially 1 B/A 3. It is preferred that the polyurethane-urea-polyaminc has a molecular Weight of 5.000 to 100.000.

In the chain extender of the formula (1 there are present hydroxyl groups capable of reacting with isocyanate groups. but the reaction between the hydroxyl and isocyanate groups does not substantially proceed. because the rate of the reaction between primary or secondary amino groups and the isocyanate groups is much higher than the rate of the reaction between the hydroxyl groups and the isocyanate groups and because the number of primary and secondary amino groups is greater than the number of isoeyanatc groups. Accordurea-prepolymer are rendered amphotcric by reacting the polyurethane-urea-polyamine with a lactonc. sul tone or sodium monohalogenated carboxylate in an amount sufficient to cmulsify the final polymer. or by reacting the polyurcthane-ureapolyamine with an acrylate or methacrylate. or acrylonitrile and hydrolyzing the reaction product. When the resulting polymer is mixed with water. an amphoteric self-emulsifiable polyurethane emulsion is obtained. The solvent used for the reaction can be distilled off under heating. and the stability of the emulsion is not at all degraded by distillation of the solvent.

As the sultone. in this invention. it is preferred to employ l.3-propancsultone and l.4-butanesultone. As the lactonc. it is preferred to employ B-propiolactone. 'y-butyrolactone. e-caprolactone and S-valerolactone.

As the sodium monohalogenated carboxylate having the formula X'(CH. ,),,COONa, in which X is a halogen atom and n is an integer of l to 2. there can be mentioned. for example. sodium monochloroacetate. sodium monochloropropionate. sodium monobromoacetate. sodium monobromopropionate. sodium monoiodoacetate. sodium monoiodopropionatc. sodium monofluoroacetatc and sodium monofluoropropionate. Among them. sodium monochloroacetate is preferred for carrying out the process on an industrial scale.

The reaction between the polyurcthancureapolyaminc and the above compound for rendering the amino groups amphoteric is generally conducted at a temperature of +40 to +C. for 3 to 7 hours. Completion of the reaction is confirmed based on the emulsifted state observed when water is added to the reaction mixture and the mixture is agitated.

As the acrylate or methacrylate. it is preferred to use methyl acrylate. ethyl acrylate. methyl mcthacrylate and ethyl acrylate. Acrylonitrile can also be used.

The reaction between the polyurethane-ureapolyamine and the above acrylates and methacrylates is generally conducted at a temperature of 50 to C for 3 to 7 hours. Thereafter the ester groups are hydrolyzed by adding an aqueous solution of an alkali and conducting hydrolysis at a temperature of from 40 to 70C. for from 2 to 5 hours.

In general. the primary. and secondary amino groups in the polyurethane-urea-polyamine are rendered amphoteric by reacting the polyurethane-urea-polyamine with an amphoteric compound (the above-mentioned specific sultone. lactone. sodium monohalogenated carboxylate or lower alkyl acrylate) in an amount sufficient to emulsify the final polymer. It is preferred that the mole ratio of such amphoteric agent to the total amino groups in the polyurethane-urea-polyamine is within the range of 0.521 to 2.0:].

The polyurethane emulsion prepared according to the process of this invention is a so-called selfemulsifiable emulsion free of an emulsifier. But in order to improve the stability of the emulsion. it is permissible to add a known emulsifier in such an amount as will not drastically change the properties of the polyurethane resin.

According to the foregoing process. according to the invention. there can be obtained a low viscosity emulsion having ordinarily a resin content of to 50 weight percent. The most prominent advantage of this invention is that the polyurethane resin contained is the thusformcd emulsion contains a reactive group CH- CH(OH )CH X, in which X is Cl or Br. which can form cross-linkages under heating.

' When the polyurethane emulsion prepared according to this invention is impregnated into fibrous materials, non-woven fabrics. paper. leather. rubber. wood. mctals. glass or plastics or is coated or sprayed on surfaces of these substrates and then the emulsion is dried. films having improved touch and surface coatings of improved properties can be obtained. Further. the emulsion prepared according to the process of this inventioh can be used in the fields of civil engineering and construction and also as an adhesive or the like.

This invention will now be further described by reference to the following illustrative Examples which by no means limit the scope of this invention.

In the Examples. all references to "parts" and percent" are on a weight basis unless otherwise indicated.

EXAMPLE 1 1. 103 parts of diethylene triamine were dissolved in 103 parts of methyl ethyl ketone. and the solution was charged into a round-bottom flask equipped with an agitator and a thermometer. A solution formed by diluting 30.8 parts of epichlorohydrin with 30.8 parts of methyl ethyl ketone was added dropwise to the above solution over a period of minutes at a temperature of to C, and the mixture was reacted under agitation at C for 1.5 hours to obtain 'a solution of a chain extender.

The product contained covalently bonded chlorine but was free of cpoxide groups.

2. 327 parts of polytetramethylene ether glycol (OH value 54.9) dehydrated at 1 10C under 30 mm Hg for 1 hour. 164 parts of benzene and 55.7 parts of a tolylene diisocyanate isomeric mixture of a 2.4/2.6- molar ratio of 80/20 were charged in a flask equipped with a thermometer and an agitator, and the mixture was reacted under agitation at 75C for 1.5 hours to obtain a solution of a urethane prepolymer having an isocyanate content of 2.43 percent.

8. l 1 parts of the thus-formed chain extender solution (concentration of percent) was diluted with 200 parts of methyl ethyl ketone. and the diluted solution was well blended in a separable flask equipped with a thermometer and an agitator. Then. 89 parts of the urcthanc prepolymer solution was added dropwise to the above diluted chain extender over a period of 30 minutcs. and the mixture was reacted at 50C for 30 minutes.

A small amount of a sample was collected from the resulting polymer solution. and it was subjected to the infrared absorption spectrum analysis. It was confirmed that no absorption owing to the -NCO group was present at 2.250 cm.

Then. 2.84 parts of B-propiolactone was added to the polymer solution and the mixture was reacted at 50C for 1 hour. Then. 300 parts of water was added to the reaction product and the mixture was thoroughly blended. Methyl ethyl ketone and benzene were distilled off under reduced pressure to obtain a stable milky-white emulsion having a resin content of 20 percent.

The pH of the emulsion was 7.0. and the emulsion could be homogeneously diluted with water to various concentrations.

This emulsion was cast into a plate having a Tefloncoated surface and then was air-dried to obtain a transparent flexible film. When this film was heat-treated at 120C for 20 minutes. a film having the following properties was obtained:

percent modulus 18 Kg/cm 300 percent modulus 38 Kg/cm Tensile strength 3612 Kg/cm Elongation 720 percent COMPARATIVE EXAMPLE 1 3.2 parts of diethylene triamine diluted with 200 parts methyl ethyl kctone was charged into a roundbottom flask equipped with a thermometer and an agitator. and 89 parts of the urethane prepolymer solution obtained in Example 1 was added dropwise to the diluted triamine at 30C over a period of 30 minutes and the mixture was reacted under agitation at 50C for 30 minutes.

Then, 2.8 parts of epichlorohydrin was added to the reaction mixture, and the reaction was conducted at 50C for 1 hour. Then. 2.8 parts of B-propiolactone was added to the reaction mixture. and the reaction was further conducted at 50C for 1 hour. The reaction product was thoroughly mixed with 300 parts of water. and methyl ethyl ketone and benzene were distilled off under reduced pressure to obtain an emulsion having a resin content of 20 percent.

The mechanical properties of a film obtained from this emulsion heat-treated in the. same manner as described in Example 1 were as follows:

100 percent modulus 17 Kg/cm 300 percent modulus 30 Kg/cm" Tensile strength 282 Kg/t:m Elongation 750 percent When Example 1 (process of this invention) is compared with Comparativc Example 1. it will readily be understood that the film formed from the polyurethane emulsion prepared according to the process of this invention had unexpectedly improved mechanical properties.

EXAMPLE 2 The procedures of Example 1 were repeated in the same manner except that 4.81 parts of L3- propancsultone was used instead of 2.84 parts of B-propiolactonc and the reaction was conducted at 50C for 1 hour. In the same manner as in Example 1. 300 parts of water was added to the reaction mixture to obtain a homogeneous stable milky-white emulsion having a pH of 7.0 and a resin content of percent. This emulsion could be homogeneously diluted with water to various concentrations.

A tilm prepared from this emulsion and heat-treated in the same manner as described in Example 1 had the following mechanical properties:

100 percent modulus 21 Kgcm 300 percent modulus 34 Kg/cm" Tensile strength 208 ls'g-crn Elongation 84 percent COM PARATlVE EXAMPLE 2 The procedures of Comparative Example 1 were repeated in the same manner except that 4.81 parts of 1.3-p1'opanesultone was used instead of 2.84 parts of fi-propiolaetone and the reaction was conducted at 50C for 1 hour. Then, in the same manner as in Comparative Example 1. 300 parts of water was added to the resulting reaction product to obtain an emulsion having a resin content of 20 percent.

A film prepared from this emulsion and heat-treated in the same manner as described in Example 1 had the following mechanical properties:

100 percent modulus 20 Kg/cm" 300 percent modulus 28 Kg/cm" Tensile strength 223 Kg/cm Elongation 810 percent When Example 2 (process of this invention) is com pared with Comparative Example 2. it will readily be understood that the film obtained from the emulsion prepared according to the process of this invention had unexpectedly improved mechanical properties.

' EXAMPLE 3 A solution of 103 parts of diethylene triamine in 103 parts of methyl ethyl ketone was charged in a roundbottom flask equipped with a thermometer and an agitater. and a solution of 92.5 parts of epichlorohydrin in 92.5 parts of epichlorohydrin was added dropwise to the above solution over a period of minutes at 30 to C. The mixture was reacted at 45C for 1.5 hours to obtain a solution of a chain extender free of epoxide groups but containing covalently-bonded chlorine.

Separately. 202 parts of polytetramethylene ether glycol (OH value of 55.3) dehydrated at 100C under 10 mm Hg for 1 hour. 90 parts of benzene and 34.8 parts of an 80 z 20 mixture of 2.4- and 2.6-tolylene diisoeyanates were reacted under agitation at 80C to form a solution of a urethaneprepolymer having a terminal isocyanate group content of 2.50 percent.

Another flask equipped with an agitator and a thermometer was charged, with 14.5 parts of the above chain extender solution and 250 parts of methyl ethyl ketone. and 100 parts of the above prepolymer solution was added dropwise to the mixture over a period of 2 hours at a temperature maintained at 10C by external ice cooling. Then. the reaction was conducted at C for 30 minutes.

Then. 5.2 parts of methyl acrylate was added to the reaction mixture and the reaction was conducted at C for 5 hours under agitation. Then. a solution of 1.0 part of sodium hydroxide in 20 parts of water was added to the reaction -mixture. and the mixture was heated at 60C for 3 hours under agitation to hydrolyze the methyl ester.

Then. 200 parts of water was added to the resulting polymer solution. and benzene and methyl ethyl ketone were distilled off under reduced pressure and the concentration was adjusted by addition of water.

Thus was obtained a low viscosity stable emulsion having a resin content of 25 percent.

1n the preparation of this polyurethane emulsion. if the methyl acrylate addition reaction or the methyl ester hydrolysis reaction were insufficient. when 200 parts of water was added. gelation was caused to occur or the resulting emulsion became unstable. Accordingly. it is important that both of the above two reactions should be conducted sufficiently.

A film prepared from this emulsion and heat-treated in the same manner as described in Example 1 had the following properties:

percent modulus l7 Kg/em" 300 percent modulus 23 Kg/cm" Tensile strength 308 Kg/em" Elongation 770 percent EXAMPLE 4 parts of methyl ethyl ketone and they were blended thoroughly. A solution formed by diluting parts of the above urethane prepolymer with 100 parts of benzone was added dropwise to the above mixture over a period of 20 minutes at a temperature maintained at 20C. and then the mixture was maintained at 50C for 30 minutes.

Then. 14.7 parts of B-propiolactone was added to the resulting reaction mixture. and the reaction was conducted at 50C for 2 hours under agitation. Then. 600 parts of water was placed into the resulting reaction mixture and thoroughly blended therewith. Then, the solvents were distilled off under reduced pressure and .the concentration was adjusted by addition of water to obtain a homogeneous stable semi-transparent emulsion having a resing content of 20 percent.

A film prepared from this emulsion and heat-treated in the same manner as described in Example 1 had the following mechanical properties:

100 percent modulus 300 percent modulus Tensile strength Elongation 22 Kg/cm 47 Kg/cm" 23o Kgjcm" 580 percent EXAMPLE 5 obtain a solution of a urethane prepolymer having a terminal isocyanate group content of 1.69 percent.

Another round-bottom flask was charged with l8.5 of the chain extender solution obtained in Example 3 and 400 parts of acetone. and 200 parts of the above urethane prepolymer solution was added dropwise to the mixture over a period of 35 minutes at a temperature maintained at 5C. Then. the mixture was heated at 50C for minutes under agitation.

Then. 7.5 parts of propanesultone was added to the above reaction mixture. and the reaction was conducted at 60C under agitation for l .5 hours. Then. 400 parts of water was placed into the reaction mixture and blended therewith. and acetone and methyl ethyl ketone were distilled off under reduced pressure. Then. the concentration was adjusted by addition of water.

There was obtained a milky-white homogeneous stable emulsion having a resin content of 20 percent.

A film prepared from this emulsion and heat-treated in the same manner as in Example l had the following mechanical properties:

l00 percent modulus 28 Kg/cm' 300 percent modulus (13 kg/cm Tensile strength 34o kg/cm Elongation 520 percent The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

l. A process for preparing an amphoteric polyurethane emulsion, which comprises.

1. reacting. in the liquid phase and in a ketone solvent. at a temperature of from -20 to +70C, (A) isocyanate-terminated urethane prepolymer prepared by reacting organic polyol having a molecular weight in the range of from 200 to 10,000 with an excess of organic polyisocyanate. with (B) an excess of polyalkylene polyamine having at least two primary or secondary amino groups and also having a functional group of the formula CH- CH(OH)CH. ,X. wherein X is chloro or bromo. the total mole number of primary and secondary amino groups in the polyalkylene polyamine being greater than the total mole number of isoeyanate groups in the isoeyanate-terminated urethane prepolymer. the reaction being carried out until the presence of NCO groups cannot be detected. whereby to form polyurethaneureapolyamine. 7 reacting. in the liquid phase the reaction product of step 1 with either a. a substance selected from the group consisting of sultones. lactones and sodium monohalogenated carboxylate. at a temperature of +40 to +70C. for 3 to 7 hours, the amount of said substance being in the range of 0.5 to 2.0 moles per one mole of amino groups of the polyurethane-ureapolyamine and sufficient to render amphoteric the amino groups of the reaction product of step 1 so that a stable emulsion is formed when water is added and blended in the product of step 2(a),

or b. a substance selected from the group consisting of alkyl acrylates. alkyl methacrylates and acrylonitrile. at a temperature of 50 to C, for 3 to 7 hours and then hydrolyzing the reaction products. the amount of said substance in the range of 0.5 to 2.0 moles per the mole of amino groups of the polyurethane-urea-polyamine and being sufficient to render amphoteric the amino group of the reaction product of step I so that a stable emulsion can be formed when water is added and blended in the product of step 2(b).

3. treating the product of step 2 to remove the or ganic solvent therefrom and adding water thereto and thereby obtaining an aqueous amphoteric polyurethane emulsion as a final product.

2. A process according to claim I. in which the reactant (B) includes up to 50 percent. by molecular equivalent. of diamines of alkylene oxide adducts. acrylonitrile adducts or acrylate adducts of diamines.

3. A process according to claim 1. in which the ratio of (b) the total mole number of amino groups containing active hydrogen atoms in the polyalkylene polyaminc. to (a) the total mole number of isocyanate groups in said urethane prepolymer is in the range of l I) 5/41.

4. A process according to claim I, in which the polyalkylcne polyaminc has the formula wherein X is Cl or Br. A is a secondary or tertiary amino group and R is alkylene having at least one primary or secondary amino group. provided that the sum of the primary and secondary amino groups in the polyalkylene polyamine is at least two.

5. A process according to claim 4, in which said polyalkylene polyamine is prepared by reacting, at from 10 to 80C. for from 0.5 to 5 hours, epiehlorohydrin epibromohydrin with a polyamine having the formula wherein n is an integer larger than one. 1 is an integer from 2 to 4 and R is hydrogen. alkyl having one to 4 carbon atoms or hydroxyalkyl having one to 4 carbonl atoms.

6. A process according to claim 1, in which the step 2(a) said substance is selected from the group consisting of 1.3-propanesultone. i,4-butanesultone, B-propiolactone. y-butyrolactone, e-caprolactone, 8-valerolactone and X(CH ),,COONa. in which X is halogen and II is an integer of 1 or 2.

7. A process according to claim 1, in which in step 2(b) said substance is selected from the group consisting of methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate and acrylonitrile.

8. An aqueous amphoteric polyurethane emulsion prepared by the process of claim 1.

9. A polyurethane molded product prepared by forming the emulsion of claim 8 into a molded product and then heat-treating the product to effect cross-linking.

l l l UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 903 032 Dated September 2, 1975 Kazuo Matsuda, Hidemasa Ohmura Inventor(s) and Hirakazu Aritaki It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Col. 12, line 23; please change the formula to:

--- l b/a 5 Col. 12, line 49; change "the step" to --in step--.

Signed and Scaled this Eleventh Day of January 1977 [SEAL] AIIeSI.

RUTH C. MASON C. MARSHALL DANN Arresting Officer Commissioner oflalents and Trademarks 

1. REACTING IN THE LIQUID PHASE AND IN A KETONE SOLVENT AT A TEMPERATURE OF FROM -20* TO +70*C (A) ISOCYANATE-TERMINATED URETHANE PREPOLYMER PREPARED BY REACTING ORGANIC POLYOL HAVING A MOLECULAR WEIGHT IN THE RANGE OF FROM 200 TO 10,000 WITH AN EXCESS OF ORGANIC POLYISOCYANATE WITH (B) AN EXCESS OF POLYALKYLENE POLYAMINE HAVING AT LEAST TWO PRIMARY OR SECONDARY AMINO GROUPS AND ALSO HAVVING A FUNCTIONAL GROUP OF THE FORMULA-CH2CH(OH)-CH2X WHEREIN X IS CHLORO OR BROMO THE TOTAL MOLE NUMBER OF PRIMARY AND SECONDARY AMINO GROUPS IN THE POLYALKYLENE POLYAMINE BEING GREATER THAN THE TOTAL MOLE NUMBER OF ISOCYANATE GROUPS IN THE ISOCYANATE TERMINATED URETHANE PREPOLYMER THE REACTION BEING CARRIED OUT UNTIL THE PRESENCE OF -NCO GROUPS GROUPS CANNOT BE DETECTED WHEREBY TO FORM POLYURETHANE UREA-POLYAMINE,
 1. A PROCESS FOR PREPARING AN AMPHOTERIC POLYURETHANE EMULSION WHICH COMPRISES,
 2. reacting, in the liquid phase the reaction product of step 1 with either a. a substance selected from the group consisting of sultones, lactones and sodium monohalogenated carboxylate, at a temperature of +40* to +70*C, for 3 to 7 hours, the amount of said substance being in the range of 0.5 to 2.0 moles per one mole of amino groups of the polyurethane-urea-polyamine and sufficient to render amphoteric the amino groups of the reaction product of step 1 so that a stable emulsion is formed when water is added and blended in the product of step 2(a), or b. a substance selected from the group consisting of alkyl acrylates, alkyl methacrylates and acrylonitrile, at a temperature of 50 to 80*C, for 3 to 7 hours and then hydrolyzing the reaction products, the amount of said substance in the range of 0.5 to 2.0 moles per the mole of amino groups of the polyurethane-urea-polyamine and being sufficient to render amphoteric the amino group of the reaction product of step 1 so that a stable emulsion can be formed when water is added and blended in the product of step 2(b),
 2. REACTING IN THE LIQUID PHASE THE REACTION PRODUCT OF STEP 1 WITH EITHER A. A SUBSTANCE SELECTED FROM THE GROUP CONSISTING OF SULTONES LACTONES AND SODIUM MONOHALOGENATED CARBOXYLATE AT A TEMPERATURE OF 40% TO +70*C FOR 3 TO 7 HOURS THE AMOUNT OF SAID SUBSTANCE BEING IN THE RANGE OF 0.5 TO 2.0 MOLES PER ONE OF AMINO GROUP OF THE POLYURETHANE UREA-POLYAMINE AND SUFFICIENT TO RENDER AMPHOTERIC THE AMINO GROUPS OF THE REACTION PRODUCT OF STEP 1 SO THAT A STABLE EMULSION IS FORMED WHEN WATER IS ADDED AND BLENDED IN THE PRODUCT OF STEP 2(A) OR B. A SUBSTANCE SELECTED FROM THE GROUP CONSISTING OF ALKYL ACRYLATES ALKYL METHACRYLATES AND ACRYLONITRILE AT A TEMPERATURE OF 50 TO 80*C FOR 3 TO 7 HOURS AND THEN HYDROLYZING THE REACTION PRODUCTS THE AMOUNT OF SAID SUBSTANCE IN THE RANGE OF 0.5 TO 2.0 MOLES PER THE MOLE OF AMINO GROUPS OF THE POLYURETHANE UREA-POLYAMINE AND BEING SUFFICIENT TO RENDER AMPHOTERIC THE AMINO GROUP OF THE REACTION PRODUCT OF STEP 1 SO THAT A STABLE EMULSION CAN BE FORMED WHEN WATER IS ADDED AND BLENDED IN THE PRODUCT OF STEP 2(B).
 2. A process according to claim 1, in which the reactant (B) includes up to 50 percent, by molecular equivalent, of diamines of alkylene oxide adducts, acrylonitrile adducts or acrylate adducts of diamines.
 3. A process according to claim 1, in which the ratio of (b) the total mole number of amino groups containing active hydrogen atoms in the polyalkylene polyamine, to (a) the total mole number of isocyanate groups in said urethane prepolymer is in the range of 1 < b < or = 5/a.
 3. TREATING THE PRODUCT OF STEP 2 TO REMOVE THE ORGANIC SOLVENT THEREFROM AND ADDING WATER THERETO AND THEREBY OBTAINING AN AQUEOUS AMPHOTERIC POLYURETHANE EMULSION AS A FINAL PRODUCT.
 3. treating the product of step 2 to remove the organic solvent therefrom and adding water thereto and thereby obtaining an aqueous amphoteric polyurethane emulsion as a final product.
 4. A process according to claim 1, in which the polyalkylene polyamine has the formula
 5. A process according to claim 4, in which said polyalkylene polyamine is prepared by reacting, at from 10* to 80*C, for from 0.5 to 5 hours, epichlorohydrin epibromohydrin with a polyamine having the formula
 6. A process according to claim 1, in which the step 2(a) said substance is selected from the group consisting of 1,3-propanesultone, 1,4-butanesultone, Beta -propiolactone, gamma -butyrolactone, epsilon -caprolactone, delta -valerolactone and X(CH2)nCOONa, in which X is halogen and n is an integer of 1 or
 2. 7. A process according to claim 1, in which in step 2(b) said substance is selected from the group consisting of methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate and acrylonitrile.
 8. An aqueous amphoteric polyurethane emulsion prepared by the process of claim
 1. 9. A polyurethane molded product prepared by forming the emulsion of claim 8 into a molded product and then heat-treating the product to effect cross-linking. 